Method for evaporation and possible distillation of fluids using a heat pump.

ABSTRACT

The invention concerns a method for evaporation and possibly distillation of liquids by means of a heat pump. By using a heat pump ( 2 ), energy is taken from energy reservoirs ( 1 ) such as rivers, lakes, sea water, air, sun or ground heat. It is however difficult to obtain temperatures to evaporate water at atmospheric conditions. According to the invention, low temperature heat is utilized by means of a heat pump by using the condenser (high pressure part) of the heat pump to evaporate liquids in an evaporator ( 4′ ) at a pressure lower than the atmospheric pressure, and thus at a lower evaporation temperature. A pump or a compressor ( 10 ) after the evaporator ( 4′ ) together with a pressure reducing device ( 9 ) at the inlet of the evaporator ( 41 ) ensures lower evaporation pressure. To fully utilize the heat energy from the heat pump, the liquids may be preheated in heat exchangers ( 5 ) before the pressure reducing means, or as part of the same means. To achieve higher temperature and pressure of the evaporated liquids, said liquids are further compressed by means of compressors ( 10 ), or alternatively by heating in intermediate heat exchangers ( 11 ) in order to achieve the desired temperature level. In the case of distillation, one stage will be required for each distillate. In addition to compressors ( 10 ), intermediate heat exchangers ( 11 ) and draining devices ( 12 ), pumps ( 13 ) are required to maintain desired recondensation pressure, possibly also valves ( 14 ) to insure correct dosing of residual products and distillates to collecting devices ( 15 ).

The invention concerns a method for evaporation of liquids with assistance of a heat pump, both for production of evaporated liquids for industrial and other technical purposes, as well as for distillation.

KNOWN TECHNOLOGY

Evaporation of liquids is required in many processes. Both for distribution of energy—were a typical example is production of steam, or in distillation processes were the most common is production of ethanol from a fermented sugar and water solution.

Steam from water is used for a variety of purposes due to the waters thermal properties with a relatively high heat capacity in all three phases, as well as a relatively high melting and vaporization heat rate (enthalpy of melting and vaporization). This last property is also one of the problems with production of steam. A lot of energy is used to evaporate water. Traditionally this has been done by heating water in boilers by the use of traditional energy sources as oil and gas, coal or electricity. Earlier, as in the first steam locomotives wood were also used.

By use of a heat pump large amount of energy can be obtained from vast energy reservoirs like rivers, lakes, ocean, air, sun or the ground. The problem is to obtain a sufficiently high temperature to make water evaporate. The waters boiling temperature is a 100° C. by 1 atm. or 101.3 kPa.

SHORT DESCRIPTION OF THE INVENTION

The invention is to use the low temperature heat produced by the heat pumps condenser to evaporate liquids under low pressure, and thereby low temperature. If as an example one reduces the pressure water is evaporated under to 10 kPa (appr. 0.1 atm) the evaporating temperature will drop to 45.8° C. Most refrigerants on the market today have a maximum condensation temperature under or just above 100° C. This is to low to evaporate water by atmospheric pressure.

By reducing the evaporation pressure it is as an example possible to use a heat pump to evaporate water under low pressure. To make steam at higher pressure and temperature require it to be compressed by a compressor after evaporation. The advantage with the invention is that one uses energy from a natural energy reservoir for the most energy intensive part of the steam production—which is the phase transition from liquid to gas.

The same problems as described above will also arise by evaporation of liquids for distillation. Typical is the production of alcohol in various forms, and also for the production of pure ethanol based on the fermentation of sugar dissolved in water.

Also for other distillation processes, or processes for separation of liquids can the invention be used. Typical for this last processes are separation of oil products from tar- or oil- sand.

DESCRIPTION OF FIGURES

FIG. 1) is an embodiment of the invention where the method is exemplified with a process to extract to distilled products from a liquid.

FIG. 2) is a detail for a possible design of a regulation device (17) for the control of the level of the liquids in the evaporator (4′).

DETAILED DESCRIPTION OF THE INVENTION

-   1) Energy reservoir for the heat pump. This can be rivers, lakes,     sea water, air, sun or ground heat. (Illustrated in FIG. 1 as the     cross section of a river.) -   2) The heat pumps evaporator. This is the heat pumps low pressure     side where the refrigerant is heated and evaporated by the heat     reservoir. -   3) The heat pumps compressor. Here the refrigerant is compressed to     a higher pressure and temperature. This to enable the water or     liquid to evaporate in the next stage. -   4) The heat pumps condenser. (see item 4′) This is the heat pumps     high pressure side of a heat exchanger where the refrigerant is     cooled off and recondensed by the water or liquids that are to be     evaporated. -   5 a,b, . . . )The heat pumps possible extra heat exchangers for     extra cooling of the refrigerant. (see item 5′a,b, . . .) Dependent     on the operation of the system and the refrigerant's thermal     properties, it may be possible to utilize the refrigerant's energy     in condensated state on the heat pump's high pressure side to     preheat the water or liquids that are to be evaporated. For best to     utilize this energy the preheating can be performed in multiple     stages. Alternatively the energy can be used for other purposes. -   6) The heat pumps pressure reduction valve. This valve reduces the     pressure from the heat pump's high pressure side to its low pressure     side. This alters the refrigerant's evaporation-     /saturation-temperature and will bring the refrigerant to evaporate     again on the low pressure side. -   7) Device for supply of water or liquids to be evaporated This is     the water intake or inlet of liquids to be evaporated, alternatively     tank(s) or container(s) with the same. -   8) Possible supply pump or feeding device for water or liquids. This     device may be required if there by various reasons are large drops     of pressure on the supply side, or it is required to measure out the     supply of water or liquids. -   5′a,b, . . . )Heat exchangers for preheating of water or liquids to     be evaporated. (see item 5 a,b, . . . ) Dependent on the operation     of the system and the refrigerant's thermal properties, it may be     possible to utilize the refrigerant's energy also in condensated     state on the heat pump's high pressure side to preheat the water or     liquids that are to be evaporated. For best to utilize this energy     the preheating can be performed in multiple stages. -   9) Possible pressure reduction valve or device to control the     evaporation pressure for the water or liquid that is to be     evaporated. To obtain the pressure required to evaporate the water     or liquids, a valve or other device may be required on the supply     side. Alternatively can a high column (riser) be used, where the     density and gravity of the water or liquids helps reducing the     pressure. Or a combination of those two methods can be used. -   4′) The evaporator. (see item 4) This is the heat exchanger were the     water or other liquids are evaporated by the heat from the     refrigerant on the heat pump's high pressure side. The water or     liquids that are to be evaporated are already preheated to     evaporation temperature or higher in (5′a,b, . . . ) or will be so     in the first part of the heat exchanger. The evaporation takes place     under sufficiently low pressure. -   10) Steam compressor. This is the device that creates the low     evaporation pressure in the evaporator (4′), as well as compressing     the steam or evaporated liquids to the required pressure for further     use. This compressor will act as a first stage in a distillation     process. -   10′) Steam compressor for multiple stages in a distillation process.     This compressor will compress the evaporated liquids to the next     heat exchanger to extract the next distilled product. Dependent on     how many components there are to extract this stage will be repeated     the required number of times in order to separate all the distilled     components. -   11) Intermediate heat exchanger. (see item 16) This is the first of     possible multiple stages of heat exchangers to either heat the steam     further, or recondensate one component after another in a series of     distilled products. -   11′) Intermediate heat exchanger. (see item 16′) This is the     possible second stage of heat exchangers. Normally this will be one     of possible more stages in a distillation process. -   11″) Intermediate heat exchanger. (see item 16″) This is possibly     the next stage in a multiple distillation process. The remaining     evaporated liquids are directed to a new compression stage, or when     all distilled products are extracted the remaining residuals are     directed to outlet (20). Dependent on how many components there are     to extract, this stage together with steam compressor for multiple     stages (10′) will be repeated the required number of times in order     to separate all the distilled components. -   12) Drainage device for remaining not evaporated products. This is a     possible outlet or drainage for those products that are not to be     evaporated in a distillation process. If the liquid to be distilled     is saltwater this device also must be able to remove salt and other     solids. -   12′) Drainage device for evaporated and then recondensated     residuals. This is a possible outlet or drainage for those liquids     that are partially evaporated in the evaporator (4′) but not wanted     as distilled products. Normally this one is not used. Another way is     to design the intermediate heat exchanger (11) in a way so that     these recondensated residuals will flow back to the evaporator (4′)     and be drained by the possible drainage device or outlet (12). -   12″) Drainage device for distilled products. This is where the first     distilled product is drawn off. -   12″′) Drainage device for distilled products. This is where the next     distilled product is drawn off. Dependent on how many components     there are to extract this stage together with steam compressor for     multiple stages (10′) and intermediate heat exchanger (11″) will be     repeated the required number of times in order to separate all the     distilled components. -   13) Pump for not evaporated residuals in a distillation process. It     is necessary with a pump or other device to remove residuals from     the process in order to maintain the necessary low evaporation     pressure. -   13′) Pump for evaporated and then recondensated residuals. If     drainage device for evaporated and then recondensated residuals     (12′) is installed as part of the intermediate heat exchanger (11)     it will be necessary with a pump or other device to remove residuals     from the process in order to maintain the necessary low evaporation     pressure. -   13″) Pump for distilled products. It is necessary with a pump to     draw off the first distilled product from the process in order to     maintain the correct pressure true the distillation process. -   13″′) Pump for distilled products. It is necessary with a pump to     draw off the next distilled product from the process in order to     maintain the correct pressure true the distillation process.     Dependent on how many components there are to extract, this stage     together with steam compressor for multiple stages (10′),     intermediate heat exchanger (11″) and drainage device for distilled     products (12″′) will be repeated the required number of times in     order to separate all the distilled components. -   14) Valve. This one is used if the possible pump and or drainage     device (12 and 13) are not able to measure out accurately enough the     drainage of residuals in order to maintain correct evaporation     pressure in the evaporator (4′). -   14′) Valve. This one is used if the possible pump and or drainage     device (12′ and 13′) are not able to measure out accurately enough     the drainage of residuals in order to maintain correct evaporation     pressure in the evaporator (4′). -   14″) Valve. This one is used if the possible pump and or drainage     device (12″ and 13″) are not able to measure out accurately enough     the distilled products in order to maintain correct recondensation     pressure in the intermediate heat exchanger (11′). -   14″′) Valve. This one is used if the possible pump and or drainage     device (12′″and 13′″) are not able to measure out accurately enough     the distilled products in order to maintain correct r condensation     pressure in the intermediate heat exchanger (11″). Dependent on how     many components there are to extract this stage together with steam     compressor for multiple stages (10′), intermediate heat exchanger     (11″), drainage device for distilled products (12′″) and pump for     distilled products (13′″) will be repeated the required number of     times in order to separate all the distilled components. -   15) Drainage device or tank for residuals. (see item 21) If the     residuals from a distillation process have to be collected or     processed further, it will be necessary to collect them in a tank.     Otherwise these are directed to a waste outlet. -   15′) Container or tank for distilled products. (see item 21′) Here     the first distilled product is collected. -   15″) Container or tank for distilled products. (see item 21′) Here     the next distilled product is collected. Dependent on how many     components there are to extract this stage, together with steam     compressor for multiple stages (10′), intermediate heat exchanger     (11″), drainage device for distilled products (12″′), pump for     distilled products (13′) and possible valve (14′″) will be repeated     the required number of times in order to separate all the distilled     components. -   16) Cooling or heater element for intermediate heat exchanger. (see     item 11) This is a cooling or heater element for a possible     intermediate heat exchanger (11). Dependent on the use of such a     system this element is either the first stage of the heat pump's     condenser (4) in order to utilize the refrigerants temperature after     compression. In this case the heat exchanger (11) will help to     increase the steam temperature in order to reduce the amount of     saturation of the steam. Alternatively the element can have its own     circuit for cooling or heating of the evaporated liquid. The latter     will be the case in a distillation process, where intermediate heat     exchanger (11) will be one of more stages in the process. In this     configuration the element could be connected with heat exchanger     (4),(5 a, 5 b, . . . ) to contribute to heating of the liquids in     possible pre-heaters (5′a, 5′b, . . . ) and evaporator (4′), or form     a separate circuit with one or more of these. It is also possible to     connect the element to external heat exchangers for other use. -   16′) Cooling or heater element for intermediate heat exchanger. (see     item 11′) This is a cooling or heater element for a possible     intermediate heat exchanger (11′). Dependent on the use of such a     system this element can have its own circuit for cooling or heating     of the evaporated liquid, or be connected with cooling or heater     element for intermediate heat exchanger (16). If this element has     its own circuit, this one could also be connected as described for     the circuit of element (16). -   16″) Cooling or heater element for intermediate heat exchanger. (see     item 11″) This is a cooling or heater element for a possible     intermediate heat exchanger (11″). Dependent on the use of such a     system this element can have its own circuit for cooling or heating     of the evaporated liquid, or be connected with cooling or heater     elements for intermediate heat exchangers (16 and 16′). The elements     (16, 16′, 16″, . . . ) can either be connected in series or parallel     configuration, or any combination suitable. If this element has its     own circuit, this one could also be connected as described for the     circuit of element (16). Dependent on how many components there are     to extract this stage will have to be repeated the same number of     times as intermediate heat exchanger (11″) in order to extract all     the distilled products. -   17) Device for regulating level of liquid in evaporator. (see item     4′). In order to evaporate all liquid components that are to be     separated by distillation it may be required to use some form of     level regulation in the evaporator. This can be made by installing     some form of device on the outlet for residuals (12). It may be a     flotation device in a chamber that is designed to regulate the     amount of liquid. (See detail as illustrated in FIG. 2.) This device     shall not be limited to a float in a chamber, but can be designed in     any practical form or shape. As an example in its simplest form it     can be to position the outlet or drainage device (12) in a specific     position in the evaporator (4′). -   18) Chamber for a float used for regulating level of liquid. (see     item 17) As a possible device to regulate the level of liquid in the     evaporator (4′), one can use a chamber with one or more holes to     allow liquid to flow freely. The dimensions of the chamber must be     designed to fit with the float (19) in such a way that the float can     move freely with the variations of the level of liquids in the     evaporator (4′). -   19) Flotation device for regulating level of liquid. (see item 17)     As a possible device to regulate the level of liquid in the     evaporator (4′) a float inside a chamber (18), can be used to     regulate the amount drawn off from drainage device for remaining not     evaporated products (12). By ensuring the right weight and thereby     density of the float compared to the liquids, one can ensure that     all components to be separated in a distillation process will be     evaporated in the evaporator (4′). -   20) Outlet for steam or evaporated residuals from a distillation     process. For steam production this is the stage where the steam has     reached final state for use in industrial or other processes. The     steam will be directed to whatever use it is intended for. In a     distillation process this is where the still evaporated residuals     that have no use will be let out or drawn off. For freshwater     production from saltwater this stage will not be used. -   21) Cooling element to container or supply-pipes for residuals. (see     item 15) This is the cooling element for residuals from a     distillation process. It is used to extract the heat added to the     residuals in the evaporator (4′). This element can either be     connected with heat exchangers (4), (5 a, 5 b, . . . ) to contribute     to the heating of the liquids in possible pre-heaters (5′a, 5′b, . .     . ) and/or evaporator (4′). It is also possible to connect the     element to external heat exchangers for other use. -   21′) Cooling element to container or supply-pipes for distilled     products. (see item 15′) This is the cooling element for the first     distilled product from a distillation process. It is used to extract     the heat left after recondensation in intermediate heat exchanger     (11′). This element can either be connected with heat exchangers     (4), (5 a, 5 b, . . . ) to contribute to the heating of the liquids     in possible pre-heaters (5′a, 5′b, . . . ) and/or evaporator (4′).     It is also possible to connect the element to external heat     exchangers for other use. -   21″) Cooling element to container or supply-pipes for distilled     products. (see item 15″) This is the cooling element for the next     distilled product from a distillation process. It is used to extract     the heat left after recondensation in intermediate heat exchanger     (11″). This element can either be connected with heat exchangers     (4), (5 a, 5 b, . . . ) to contribute to the heating of the liquids     in possible pre-heaters (5′a, 5′b, . . . ) and/or evaporator (4′).     It is also possible to connect the element to external heat     exchangers for other use. Dependent on how many components there are     to extract this stage will have to be repeated the same number of     times as container or tank for distilled products (15″) in order to     extract all the distilled products.

Configuration of the Invention for Three Typical Operations Based on the Example in FIG. 1:

-   A) Steam production from water. For steam production from water the     heat pump will be as described by item (1), (2), (3), (4), (5 a),     possibly (5 b)—to utilize the heat-energy to the optimum, and (6).     The water intake (7) will normally be from a reservoir or a     water-pipeline. Dependent on the supply of water a water-pump (8)     may or may not be required. To preheat the water a pre-heater (5′a)     and possibly (5′b) will be used. Dependent on the height from the     water-intake (7) or the water-pump (8) to the evaporator (4′) a     pressure reduction valve (9) may or may not be required to ensure a     low evaporation pressure. The evaporator (4′) is where the water is     evaporated. An intermediate heat-exchanger (11) together with a     heater element (16) can be used to reduce the saturation of the     steam before the steam compressor (10). The steam will then go to     outlet (20) for use in other processes. -   B) Distillation of ethanol from a fermented sugar solution with     water. For distillation of ethanol the heat pump will be as     described by item (1), (2), (3), (4), (5 a), possibly (5 b)—to     utilize the heat-energy to the optimum, and (6). The intake of     liquid (7) will be from a tank with the fermented sugar solution.     Dependent on the supply a pump (8) may or may not be required. To     preheat the liquid a pre-heater (5′a) and possibly (5′b) will be     used. Dependent on the height from the intake (7) or the supply pump     (8) to the evaporator (4′) a pressure reduction valve (9) may or may     not be required to ensure a low evaporation pressure. The evaporator     (4′) is where the ethanol is evaporated. Normally a device for     control with the level of liquid (17) in the evaporator (4′) will be     used to regulate the drainage of the residual liquids thru an outlet     or other drainage device (12). The residual liquids are pumped with     a pump (13) alternatively thru a valve (14) to an outlet or     container or tank for the residual liquids (15). The evaporated     ethanol is led thru a intermediate heat exchanger (11) together with     a cooling element (16) that is used to recondensate whatever water     and other heavier distillates than ethanol that has been evaporated     together with the ethanol in the evaporator (4′). These     recondensated liquids are drained thru outlet (12′), with pump (13′)     alternatively thru valve (14′) to outlet or container or tank (15).     Cooling element (21) can be used to utilize these residual liquids     heat to preheat the fermented sugar solution thru pre-heater (5 a, 5     a′) and possibly (5 b, 5 b′). The evaporated ethanol together with     other lighter distillates will be compressed with compressor (10) to     another intermediate heat exchanger (11′) with a cooling element     (16′) that is used to recondensate the ethanol. The ethanol is     drained thru outlet (12″) and possibly pumped with pump (13″) thru a     possible valve (14″) to container or tank (15′). The lighter     distillates left will go to outlet (20). In cases where these     elements cause pollution problems they can be collected for further     processing. -   C) Production of freshwater from saltwater. For production of     freshwater from saltwater the heat pump will be as described by item     (1), (2), (3), (4), (5 a), possibly (5 b)—to utilize the heat-energy     to the optimum, and (6). The saltwater intake (7) will normally be     from the sea. Dependent on the supply a water-pump (8) may or may     not be required. To preheat the saltwater a pre-heater (5′a) and     possibly (5′b) will be used. Dependent on the height from the     water-intake (7) or the water-pump (8) to the evaporator (4′) a     pressure reduction valve (9) may or may not be required to ensure a     low evaporation pressure. The evaporator (4′) is where the water is     evaporated. Normally a device for control with the liquid level in     the evaporator (17) will be used to regulate the drainage of the     salt thru an outlet or other device (12). The salt will be pumped     with a pump (13) alternatively thru a valve (14) to an outlet or     container or tank (15). The steam will be compressed with     steam-compressor (10) to an intermediate heat exchanger (11′) with a     cooling element (16′) that is used to recondensate the water. The     heat collected in cooling element (16) is used to preheat the     saltwater in pre-heater (5 a-5′a, 5 b-5′b, . . . ) and possibly     evaporator (4′). The water is drained thru outlet (12″) and possibly     pumped with pump (13″) thru a possible valve (14″) to a tank or     freshwater pipeline (15′). Cooling element (21′) will be used in     parallel to cooling element (16′) to utilize the recondensated     water's heat to preheat and maybe partly evaporate the saltwater.

The method for evaporate and possibly distillation of liquids with assistance of a heat pump can be utilized by most processes where evaporation of liquids and the usage of these are integrated. Other examples are the paper and pulp industry, production of gypsum boards, extraction of oil-products from tar- or oil- sand, as well as many other industries. 

1) Method for evaporation and possible distillation of liquids with assistance of a heat pump, is designed to utilize the low temperature heat from a heat pump by using its condenser (4) (high pressure side) to evaporate liquids by a low pressure and thereby also a low evaporation temperature in an evaporator (4′), wherein using the heat generated on the heat pumps high pressure side (in the heat pumps condenser) to evaporate liquids; this is done by designing the heat pumps condenser (4) as an heat exchanger (4 and 4′) that heats up and evaporate liquids under low pressure; the evaporation pressure is reduced by either a pressure reduction valve (9), or by letting the liquid rise in a high column or pipe (riser) on the inlet side of the evaporator (4′), combined with a pump or compressor (10) for suction of the evaporated liquids out of the evaporator (4′). 2) Method for evaporation and possible distillation of liquids with assistance of a heat pump of claim 1 wherein the method requires one or more pumps or compressors (10, 10′, . . . ) in order to create and maintain a low evaporation pressure in the evaporator (4), as well as establish the right recondensation pressure for different distilled products in a distillation process, or to create a sufficiently high pressure and possibly temperature for the use of steam in industrial or other processes.) 3) Method for evaporation and possible distillation of liquids with assistance of a heat pump of claim 1 wherein the method can use one or more heat exchangers (5 a-5′a, 5 b-5′b, . . . ) in order to make full use of the heat pumps energy by also preheating the liquids before they are feed to a larger heat exchanger (4 and 4′) where the liquids are evaporated.) 4) Method for evaporation and possible distillation of liquids with assistance of a heat pump of claims 1 and 2 wherein the method either can use one or more pressure reduction devices (9) in order to obtain a correct evaporation pressure; or it can use a high heat exchanger with one or more columns or pipes (risers) where the liquid is flowing naturally using the gravitation as pressure reduction; or a combination of the above methods.) 5) Method for evaporation and possible distillation of liquids with assistance of a heat pump of claims 1 and 2 wherein the method can use a heat exchanger (11) for further heating of the evaporated liquids after evaporator (4′) to reduce the saturation of the steam before compressor (10). 6) Method for evaporation and possible distillation of liquids with assistance of a heat pump of claims 1 and 2 wherein the method can use one or more heat exchangers (11, 11′, 11″, . . . ) for either cooling of the various distilled products and residuals in a distillation process, or to heat the evaporated liquids further in order to obtain a higher temperature that compression of the evaporated liquids will give.) 7) Method for evaporation and possible distillation of liquids with assistance of a heat pump of claims 1 and 5 wherein a cooling or heater element (16) to a possible heat exchanger (11) can be connected as the first section of the heat pumps condenser (4) in order to utilize the refrigerants peak temperature in the process as it leaves the heat pumps compressor (3). 8) Method for evaporation and possible distillation of liquids with assistance of a heat pump of claims 1, 2 and 6 wherein cooling or heater elements (16, 16′, 16″, . . . ) to possible heat exchangers (11, 11′, 11″, . . . ) either can be connected in serial, parallel or any combination of these; the energy collected from heat exchangers (11, 11′, 11″, . . . ) can be used to preheat the liquids in heat exchangers (5 a-5′a, 5 b-5′b, . . . ), and maybe also to heat and evaporate liquids in the evaporator (4′). 9) Method for evaporation and possible distillation of liquids with assistance of a heat pump of claims 1, 2 and 6 wherein cooling elements (21, 21′, 21″, . . . ) ether can be connected in serial, parallel or any combination of these; the energy collected from the distilled products and residuals can be used to preheat the liquids in heat exchangers (5 a-5′a, 5 b-5′b, . . . ), and maybe also to heat and evaporate liquids in the evaporator (4′). 10) Method for evaporation and possible distillation of liquids with assistance of a heat pump of claims 1, 2, 4 and 6 wherein the method when used for distillation requires a set of drainage devices (12, 12′, 12″, 12′″, . . . ) for each of the distilled products as well as for residuals; it also requires pumps (13, 13′, 13″, 13′″, . . . ) connect after each drainage device to maintain correct recondensation pressure in each heat exchanger (11, 11′, 11″, . . . ) as well as evaporation pressure in evaporator (4′); it is possible to connect valves (14, 14′, 14″, 14′″, . . . ) after pumps (13, 13′, 13″, 13″′, . . . ) to ensure that the correct amount of distilled products and residuals are drawn off each drainage device.) 11) Method for evaporation and possible distillation of liquids with assistance of a heat pump of claims 1, 2, 6 and 10 wherein the method when used for distillation requires a device for regulation of liquid level (17) in the evaporator (4′) mounted before drainage device (12) to regulate and ensure right liquid level in the evaporator (4′). 